Implantable medical devices are often used to treat a variety of medical conditions. Examples of implantable medical devices include drug delivery devices, pain management devices, and devices that treat heart arrhythmias. One example of an implantable medical device used to treat heart arrhythmias is a cardiac pacemaker, which is commonly implanted in a patient to treat bradycardia (i.e., abnormally slow heart rate). A pacemaker includes a pulse generator and leads, which form the electrical connection between the pulse generator and the heart. An implantable cardioverter defibrillator (ICD) is used to treat tachycardia (i.e., abnormally rapid heart rate). An ICD also includes a pulse generator and leads that deliver electrical energy to the heart. Pulse generators typically include a metallic housing for a battery and electrical circuitry and a header for connecting the leads to the pulse generator.
Implantable medical devices are also useful in the treatment of heart failure. For example, cardiac resynchronization therapy (CRT) (also commonly referred to as biventricular pacing) is an emerging treatment for heart failure, which involves stimulation of both the right and left ventricles to increase hemodynamic efficiency and cardiac output. The treatment of heart failure and heart arrhythmias can be enhanced through the use of remote implanted devices. One example of such a remote device is a pressure sensor located in the vasculature. Communication between the implantable medical device and the remote device can allow the sensor data to be downloaded by a clinician used to modify the therapy delivered by the implantable medical device, or both.